You can only directly contact another user under certain circumstances.
Right now, as you are a 1 rep user, you can't, unless you asked a question or left an answer and someone else commented on it then you can "ping" them with @ followed by their user name. For example to ping me you would write @markkirby in your comment and I would receive a notification ...
StackExchange sites are intended for public questions and answers. They are not really designed for private discussion.
You can ping a specific user in comments or chat. However, they are under NO obligation to respond. They are a volunteer, and answer what they please.